This disclosure relates to energy management, and more particularly to energy management of household consumer appliances. The disclosure finds particular application to cooking appliances and is particularly advantageously applied to such appliances with electromechanically controlled oven heating elements.
Currently, utilities charge a flat rate, but with the increasing cost of fuel prices and high energy usage at certain parts of the day, utilities have to buy more energy to supply customers during peak demand. Utility companies have to find ways to temporarily provide for this higher energy use, which comes at great expense to utility companies. Consequently, utilities are charging higher rates during peak demand periods. If the utility company can communicate that power is in high demand, home appliances, such as ranges that are typically used during peak time (later afternoon), could notify the consumer that demand is high and reduce peak power usage of the appliance and allow the utility company to shed load. This “demand response” capability in cooking appliances spread over thousands of customers would allow the utility company to shed a significant amount of peak load.
One proposed third party solution is to provide a system where a controller “switches” the actual energy supply to the appliance or control unit on and off. However, there is no active control beyond the mere on/off switching.
In cooking appliances such as electric ranges, which employ surface heating units comprising resistive heating elements for surface cooking and ovens comprising resistive bake and broil units for baking and broiling respectively, the surface units are used 2-3 times more often than the oven units. The best opportunity to shed power on surface units with minimum disruption to the user is during times when a surface heating unit is being operated at high settings. High settings are typically initiated to perform non-direct-cooking related activities, such as boiling water. For normal cooking using surface units, the user typically selects power settings which are 30% or less of max power, while when bringing water to a boil the user typically selects the maximum 100% power setting.
While electronic controls for surface units can change or limit the duty cycles in response to a “high demand”, many ranges use electromechanical power switching devices such as infinite switches for surface heating units. These devices operate independently and need not interact with a microprocessor. This system provides a way to reduce peak and average power consumption of the electromechanically controlled surface heating units with minimal changes to conventional electromechanically controlled cooking appliance design, in a cost effective manner. This system is able to react to either a discrete normal demand or higher demand signal. Therefore, this system is a simple, low cost method to selectively reduce both peak and average power that does not require relatively expensive fully electronic range controls.
One method of providing low-cost reduction of peak and average power is to implement a simple demand side management “DSM” control device in an existing electromechanical appliance that will delay, adjust, or disable power consuming features to reduce power consumption. However, such a DSM device will simply switch off or reduce loads. Therefore, there exists a need for an additional feature to provide feedback regarding loads currently in use, which would enable the control to determine whether to deactivate, reduce, or maintain the current power load.